Managing Receptors

To view and edit receptors, right click a scenario in the Project Browser, then select Edit Receptors from the Scenario Context Menu. This will open an interactive dialog where Discrete, Ring or Uniform Grid receptors can be defined.

SOFEA uses the concept of a Receptor Group to organize receptors. For grid receptors, this corresponds to Netid for GRIDCART receptors in AERMOD. For discrete receptors, including rings, this corresponds to Arcid for EVALCART receptors in AERMOD.

The plot on the right-hand side shows all sources and receptors already defined within a Scenario. As receptors are added through the interactive dialog box, they are automatically added to the plot so that you can visually confirm that added receptors are placed at the desired locations. You can modify the color of group of receptors by double-clicking the square symbol in the first column of the table.

Receptor groups, discrete and grid receptors can be defined at any time. As ring receptors are linked to source geometry, these receptors can only be defined after sources have been added to a source group.

Discrete

Add or remove discrete Cartesian receptors. To add a discrete receptor, type in X and Y receptor coordinates and terrain elevation in meters, then click Add. Added receptors will be shown on the plot to the right. Receptors can be removed by highlighting a receptor or a group of receptors within the list of receptors and clicking Remove.

In AERMOD, DISCCART keyword is reserved for discrete receptors. After you save the modifications made to the Discrete tab, the AERMOD input file will be populated with a list of RE DISCCART Xcoord Ycoord (Zelev Zhill) (Zflag) entries. Here, Xcoord and Ycoord will correspond to inserted coordinates, Zelev and Zhill to entered elevation or to 0 if elevation was not entered and Zflag to receptor flag height entered in the General Source setting (default is 1.5 m).

Rings

Add a special type of discrete Cartesian receptors defined with the EVALCART keyword in AERMOD, once the sources are defined in Scenario. These receptors are similar to discrete receptors defined with the DISCCART keyword, but EVALCART also allows for grouping of receptors, in this case along equidistant “rings” surrounding a source or a group of sources.

This set of receptors is especially useful for fumigation applications when concentrations at the specific distances from the area source are needed. Module within SOFEA creates receptors at the equal distance from the edge of all area sources specified in the Buffer distance field. Receptors are placed around the entire group of adjacent sources rather than within any source, as demonstrated in the plot below.

From the drop down menu select the Source Group for which Rings of receptors are desired. Type in Buffer distance and Receptor spacing in meters, then click Add. Added receptors will automatically appear on the plot to the right.

As you save the modifications made to the Rings tab, the AERMOD input file will be automatically populated with a list of RE EVALCART Xcoord Ycoord Zelev Zhill Zflag Arcid using the information associated with the rings that were created: Xcoord and Ycoord will correspond to the coordinates of created Ring receptors, Zelev and Zhill will be entered as 0, Zflag will correspond to the receptor flag height entered in the General Source setting (default is 1.5 m), and Arcid will correspond to the names of the created rings.

Warning

Receptor rings will not automatically update if source geometry changes, or sources are added or removed from the source group. To update rings, you must select the group and click Update in the Receptor Editor.

Uniform Grid

Add or remove Cartesian grid receptor networks, defined with GRIDCART keyword in AERMOD. To add gridded receptors, enter coordinates of the starting grid location – this is the southwest corner of the gird. Enter the number of receptors along the x and y-axis and required distance in meters between the receptors in x and y directions. Then press Add. Added receptors will automatically appear on the plot to the right.

As you save the modifications made to the Uniform Grid tab, the AERMOD input file will be populated with RE GRIDCART Netid lines where Netid represent receptor network identification code automatically generated in SOFEA. Start and the end of the grid network will be indicated with STA and END parameters. Parameters entered in the Uniform Grid tab will be saved in AERMOD file in this format: RE GRIDCART Netid XYINC Xinit Xnum Xdelta Yinit Ynum Ydelta where Xinit and Yinit correspond to the coordinates entered in the Starting grid location field, Xnum and Ynum correspond to the values entered in the Receptor count field, and Xdelta and Ydelta correspond to the values entered in the Receptor spacing field.